The play by Oscar winner Dustin Lance Black made its Broadway debut last year in similar starry fashion. Saturday's benefit performance was broadcast live on YouTube, where director Rob Reiner said it drew 200,000 viewers. He hopes it attracts more than a million before its weeklong online run ends. The play will also be staged around the country with local actors at colleges and community theaters.

"We want as many people as possible to see what happened inside that courtroom," said Reiner, a founding member of the American Foundation for Equal Rights, which is helping fund the federal fight for marriage equality.

Relying largely on transcripts from court proceedings, "8'' introduces viewers to the couples who challenged the California initiative, the attorneys who argued their case and a bumbling witness who spoke out against them.

One couple has two children together; the other wants to start a family; and a witness testifying in favor of the same-sex marriage ban said under oath that marriage equality was best for couples, kids and the country.

"We did put fear and prejudice on trial, and fear and prejudice lost," Olson said after Reiner brought him on stage.

Olson, a noted conservative litigator, represented George W. Bush during the contentious Florida recount that decided the 2000 presidential election and later served as his solicitor general. Boies, a prominent liberal attorney, led Vice President Al Gore's legal team in the recount.

Reiner said he and Black decided to make a play and eventually a movie based on the Prop. 8 trial after proponents successfully petitioned to block cameras from the courtroom.

Saturday's reading was held on a courtroom-like set, with eight chairs on each side and Pitt's judge's box in the center. Sheen and Clooney made for an impressive legal team, while Reilly cracked up the crowd as a verbose marriage expert.

"I knew that Martin Sheen was going to get a huge ovation after that speech because we applauded for him in rehearsal," said Ferguson, adding that he wanted to be in "8'' as soon as he heard about it. "John C. Reilly did a brilliant job with his role but I loved seeing Jane Lynch play such a villainous, homophobic creature. It really felt like she was sticking it to the man."

Actor George Clooney, left, and actor Jansen Panettiere take a bow during the curtain call at the Lo …

Reilly said he was moved by the material, and even more so by its message.

"I think America will be a better place and we can hold our chins up a little higher in this country when everyone is treated (equally)," he said. "These aren't gay rights or special rights, they're basic rights that people who love each other should have."

Reilly was thrilled to participate in the play, and even took on a last-minute role change when Pitt signed on. Reilly was to play the judge, but instead jumped into a role that Reiner originally was going to play.